There is no loading system that will load more accurate ammunition than the Lee Collet Dies. We guarantee it in writing with every set. No one but Lee has ever dared make a guarantee like this "Smallest group size or your money back". A ollet squeezes the case neck against a precision madrel for a perfect bullet fit with minimum run-out. No case lube is needed. Cases last ten times longer, so the savings on only 35 cases will pay for the dies. Maximum accuracy is usually achieved by seating the bullet out far enough to touch or almost touch the rifling. This provides the shot start pressure normally supplied by the crimp. That's why a dead lenght bullet seater is included to complete the most accurate reloading system ever made. These dies size only the neck to preserve the perfect fit of fire forming. Only reload cases that have been fired in your gun. Not recommended for autoloaders, slide or lever action guns. The Lee Collet Dies set includes: Collet neck sizing die-dead bullet seating die-shellholder-powder measure-charge table and storage box.